The 1978 NCAA Men's Division I Basketball Tournament involved 32 schools playing in single-elimination play to determine the national champion of men's NCAADivision Icollege basketball. It began on March 11, 1978, and ended with the championship game on March 27 in St. Louis, Missouri. A total of 32 games were played, including a national third place game.

The process of seeding the bracket was first used in this tournament. Sixteen conference winners with automatic bids were seeded 1 through 4 in each region. At-large teams were seeded 1 through 4 in each region separately. There were in fact only 11 true at-large teams in the field, as the remaining 5 teams were conference winners with automatic bids who were seeded as "at-large."[1] The practice of distinguishing between automatic and at-large teams was ended after the tournament, and the expanded field of 40 was simply seeded from 1 to 10 in the 1979 tournament.

The biggest upset of the tournament took place in the first round, when little-heralded Miami University (Ohio) defeated defending champion Marquette 84-81 in overtime. The victory was even sweeter for Miami Redskins (now RedHawks) fans as former Marquette coach Al McGuire had earlier strongly criticized the NCAA for potentially matching Marquette against Kentucky in the second round, with Marquette being given a first-round opponent in Miami that was supposedly not even worthy of providing an adequate tune-up game.

Unranked Cal State Fullerton pulled off two upsets, first over 4th ranked New Mexico (coached by Norm Ellenberger and led by Michael Cooper) and then over top-10 San Francisco (featuring Bill Cartwright). The loss was especially painful for New Mexico as the regional semi finals and finals were scheduled on the Lobos' home court in Albuquerque. Cal State Fullerton then almost upset Arkansas in the West Regional final, losing by 3 points. In each of the 3 games, the Titans overcame second half double digit deficits. In the Arkansas game, they cut a big deficit to 1 and had the ball with 14 seconds left. But Arkansas' Jim Counce stole the ball from Keith Anderson (many observers felt Anderson was fouled) drove down to hit a clinching layup.

In the Mideast regional final, Kentucky knocked off top seeded Michigan State, led by freshman Earvin "Magic" Johnson. This was the only time in a 4-year period (that included his senior year in high school, 2 years of college, and his rookie NBA season) that Magic's team did not win its final game of the playoffs and hence, the championship.

The Final Four semifinal games and the National Championship game in St. Louis Arena (a.k.a. The Checkerdome) were not played on the Arena's official floor. Water damage to it forced the NCAA to borrow the floor from Indiana University's Assembly Hall.